Testing 89+10%E gives better MPG than 87+10%E

[Mach1Owner]

So I have a new car, still on factory fill I Have done almost 1,400 of mixed HW/City driving over 4 tanks filling @ 1/4 tank each time with WaWa brand 87oct with 10%e. I averaged 24.30MPG and $0.144 per mile.

My next 4 tanks will be with WaWa 89oct, again filling @ 1/4 tank for the next 4 tanks and taking another average. I obviously can't control factors like weather, but I am keeping a close eye on drive style and tire air pressure, and taking the same routs to the places I normally drive.

 

[Clevy]

And this whole exercise is an attempt at futility.

Try it after 20000 miles,once the engine is completely broken in.

 

[simple_gifts]

Originally Posted By: Clevy
And this whole exercise is an attempt at futility.

Try it after 20000 miles,once the engine is completely broken in.


+1; my B2300 was constipated for about 9K miles.

 

[Mach1Owner]

I don't see why that would matter. I have been getting really similar MPG for the last 4 tanks. All between 23 and 25MPG.

I also think it's [censored] that it can take 2 years of driving to "break in" an engine.

 

[SwampSurvivor]

Originally Posted By: simple_gifts
Originally Posted By: Clevy
And this whole exercise is an attempt at futility.

Try it after 20000 miles,once the engine is completely broken in.


+1; my B2300 was constipated for about 9K miles.



My 2011 Focus with it's smaller and sideways 2.0L took 15K I believe. Gas mileage shot up almost instantly at 15K

 

[sciphi]

Some engines do respond better to higher octane. Try it and see if yours does.

 

[Mach1Owner]

Originally Posted By: Miller88
Originally Posted By: simple_gifts
Originally Posted By: Clevy
And this whole exercise is an attempt at futility.

Try it after 20000 miles,once the engine is completely broken in.


+1; my B2300 was constipated for about 9K miles.



My 2011 Focus with it's smaller and sideways 2.0L took 15K I believe. Gas mileage shot up almost instantly at 15K


All FWD i4's are sideways.

I have not ever seen the MPG on my cars ever randomly go up when I've put on more miles. Aside from then I take out the factory fill and put in the oil that I will be normally using.

 

[Cardenio327]

Originally Posted By: Mach1Owner
All FWD i4's are sideways.


What about Audi's and Saab's FWD I4 engines? I had a 1990 Fox with a FWD I4 that wasn't sideways.

 

[morris]

MPG test on anything less than 5-10 tanks at a time can not be accurate. to many unknowns.

 

[Mach1Owner]

Originally Posted By: Cardenio327
Originally Posted By: Mach1Owner
All FWD i4's are sideways.


What about Audi's and Saab's FWD I4 engines? I had a 1990 Fox with a FWD I4 that wasn't sideways.


Really? I cant even picture in my head how that transmission works then. I'll have to look them up.

 

[SwampSurvivor]

Olds Toronado was front drive ... but the engine was longitudinally mounted.

 

[Clevy]

When I did my mos2 trials I tracked mileages for 15000 miles just to have a large pool of data and to help see what was anomalous and what was common.

 

[Mach1Owner]

The problem with a bit that large is that you could just end up wasting money for 15,000 miles.

If I end up with similar MPG to the 87oct then I'll wait a few oil changes and try again. No matter what there will be a LOT of variables, but my schedule doesn't change much over 2 months, so the next 2 months should be very similar, aside from the weather warming up, which I know can impact MPG. It's almost as if to do a VERY accurate test you have to test for a full year. Which can take some planning when you want to fill up @ the same station every time.

 

[Garak]

Originally Posted By: Mach1Owner
Really? I cant even picture in my head how that transmission works then. I'll have to look them up.

My five cylinder Audi 200 front wheel drive was the same way, mounted longitudinally. A side effect is that torque steer is cut very significantly.

 

[Falcon21]

The classic Saab 900 had the engine mounted "backwards" with FWD.

Quote:
The Saab 900 is a front-engined, front-wheel-drive compact car with a longitudinally mounted, 45-degree slanted, L 4-cylinder engine, double wishbone front suspension and beam-axle rear suspension. It was originally introduced in May 1978, for the 1979 model year.[1]
Like its predecessor the 99, the 900 contained a number of unusual design features that distinguish it from most other cars. First, the engine was installed "backwards", with power delivered from the crank at the front of the car. Second, the transmission, technically a transaxle, bolted directly to the bottom of the engine to form the oil pan (albeit with separate oil lubrication). Thus, power from the crank would be delivered out of the engine at the front, then transferred down and back to the transmission below, via a set of chain-driven primary gears. In similar fashion, Minis also had their gearbox mounted directly below the engine; however, the Mini gearbox and engine shared the same oil, whereas the Saab 900 (and 99) gearboxes contained a separate sump for engine oil.

 

[Falcon21]

When I had my 1996 Saab 900 SE I found it got better fuel economy with premium gas. The owner's manual suggested running premium. Because the car is turbocharged it required the higher octane rating to get both optimal power and/or fuel economy. Running lower grades of fuel the car would somewhat limit performance to avoid knocking.

Just don't think that any car will run better with premium. If it wasn't designed to run premium, or even midgrade, then you will most likely just be wasting extra money. Usually whatever the owner's manual suggests is what's best for your car.

Your owner's manual might say how many miles until your fuel consumption will go down to its "normal" rate when breaking in the engine. For my 900 it was about 3,000 to 4,000 miles.

 

[Garak]

Originally Posted By: Falcon21
Just don't think that any car will run better with premium. If it wasn't designed to run premium, or even midgrade, then you will most likely just be wasting extra money. Usually whatever the owner's manual suggests is what's best for your car.

I'd agree. Many years ago, I used to run mid-grade in the old truck. A station here used to sell mid-grade at regular prices, so it wasn't a concern; it was actually a good selling point and kept the place busy.